Transportation configuration.
Deployment.
Man portable; deployable from unprepared surfaces.
The Drone also had capabilities that made it attractive for military applications, especially in low intensity conflicts and urban warfare . Note that such a drone would fill a needed void in locations where high altitude reconnaissance from assets such as Predator only provide the “"big picture” from above, but do not allow one to look into windows, fly into parking decks, breach obstacles, or perch on a building roof as a sentry. A militarized version of the drone known as Dragon Stalker was conceived and mocked up to illustrate its portability in the battlefield. A powered wind tunnel model was constructed to verify flight envelope analyses.
Dragon Stalker: small unit reconnaissance and fire support UAV
Dragon Stalker was a light weight twin-engine VTOL drone design capable of one-engine-inoperative flight. Due to its small footprint, it could operate from shipboard without occupying significant deck space (edge stackable), or it could be transported by small military vehicles. Dragon Stalker could be deployed from its shipping configuration by folding down its tail and locking it into place. To war-fighters could easily handle Dragon Stalker which when fueled and fitted with a payload, weighed under 200 pounds. Dragon Stalker was designed to be fully autonomous, being directed by high-level commands from the war-fighters' hand-held terminal ("takeoff", "go to waypoint Tango-Sierra-2.0", "hold at 90 feet AGL"). Dragon Stalker had a shrouded propulsors which not only afforded safety when deployed in proximity to personnel and vehicles, but they enhanced survivability in urban war zones where wire strikes are a particular threat to rotary wing vehicles. Special attention to noise control through absorptive and active methods gave Dragon Stalker the potential to be one of the quietest rotary wing drones in existence. Twin-engine reliability and an affordable design made Dragon Stalker a better idea than currently adopted approaches to small unit surveillance.
Remote Detection of Buried Natural Gas Leaks with Ground Penetration Radar (GPR)
[25] In 1985 and 1986 Robert Michelson directed a study at the Georgia Tech Research Institute through a contract sponsored by the Gas Research Institute (GRI), under a subcontract to the Philadelphia Electric Company (PECo).
Natural gas leaks occurring in buried distribution systems have caused concern within the utility industry due to the potential for environmental and safety problems which can result from even small volume leaks. Deaths and destruction of private property have occurred due to the formation of natural gas leaks in urban areas. To protect the public, utilities have instituted planned surveys of their gas distribution systems. Several methods are used to detect buried leaks. These techniques include vegetation surveys and above-ground surveys using portable gas detectors. Once gas is detected, "bar holes" are drilled in an effort to locate the specific region of the leak. Having found the probable leak location, a crew will excavate the site. An experienced leak pinpointing crew will fail to find the leak position 10% to 20% of the time, thereby requiring excavation of an adjacent site. The inaccuracy of location can often be attributed to ducting of the gas away from the actual region of the leak as a result of soil stratification or even the low resistance path caused by the distribution pipe-soil interface. Whatever the cause, the cost to the utility for a "dry hole" excavation can be as much as $1,500 depending on the area and surface preparation (pavement) which must be disturbed and restored. This is a serious cost to the industry when it is considered that it estimated 800,000 leaks are repaired in the U.S. annually.
There is an obvious need for a quick and accurate method of detecting not just the presence of a natural gas leak but its location as well. To this end, numerous methods for leak pinpointing have been investigated, including ground penetration radar and acoustic techniques (both active and passive). Michelson's team investigated the major parameters associated with the remote detection of natural gas leaks from buried utility pipes by electromagnetic means. The results of this study indicated that the recommended near-term system configuration for the detection of buried natural gas leaks was a modified bistatic approach incorporating two monostatic pulsed instrumentation radar systems separated by a fixed distance and operating within a transmitted signal frequency range of 0.1 GHz to 3 GHz.
Data gathered during this study showed laboratory measurements of dielectric constant, loss tangent, and the resulting attenuation for non-permeable samples over a broad range of frequencies roughly approximating those contained within the bandwidth of commercially available impulse ground penetration radars.
One area of vital importance which was outside the scope of this study dealt with the effect of natural gas leaks on soil characteristics, specifically how the gas actually interacts with the soil in terms of migration, desiccation, and chemical transmutation. The medium through which the energy passes must be modeled and thoroughly understood to fully apreciate how electromagnetic energy (or any other source) can be used most effectively to detect buried gas leaks.
Radio-Acoustic Techniques for Non Line-of-Sight (NLOS) Sensing
[26][27] In 1992 Robert Michelson led the Georgia Tech Research Institute team of senior engineers and scientists to develop a non line-of-sight (NLOS) sensor. In land battle scenarios, the opponent that reveals himself first will often lose in an ensuing encounter. It is therefore imperative that ground forces conduct their mission without being visible to opposing sensors. Various techniques can be employed to make ground vehicles less observable (camouflage, radar-absorbing materials, exhaust coolers, etc.), but simple tactics such as the use of terrain masking are often more effective means of increasing the survivability of a ground vehicle than any ectophoretic or deceptive devices. A major drawback with the use of terrain masking is that it tends to work both ways: not only is the masked vehicle hidden from view, but the masking terrain serves to block the sensors on the masked vehicle, thereby effectively blinding it to approaching threats.
NLOS sensor scenario showing a masked vehicle interrogating an approaching threat vehicle.
Extendable antennas/sensor heads overcome the blocked sensor problem but, if active, must be low-probability-of-intercept (LPI) systems. Also, these line-of-site sensors can actually be a target designator for hostile anti-radiation munitions if they are detected.
An alternate approach is to use bistatic sensors such as remote antennas, UAVs, or surveillance aircraft to interrogate the battlefield and report what they see to terrain-masked forces. Unfortunately this can eliminate the element of surprise, may require air superiority in the region, and really precludes the possibility of individual ground vehicles operating autonomously (i.e., without having to rely on assets such as UAVs which may not be under their control).
The technique used by geophysicists[28] to measure the temperature profile of the atmosphere from the ground by tracking the speed of propagation of acoustic waves with radar was considered for adaptation as a NLOS sensor. Under funding from the Defense Advanced Research Projects Agency, (administered through the Picatinny Arsenal), this technique was investigated as having possible application to the direction of NLOS targets while maintaining a very low probability of intercept for the interrogating platform. Essentially, a radar may be made to "look around corners." The program led by Michelson, investigated the feasibility, physical limitations, and possible methods to augment the performance of this novel technique whereby a vehicle could remain fully masked to one side by an obstacle while being able to use radar to look around the masking obstruction, thereby maintaining low observability without loss of lethality and combat effectiveness. In addition, this technique was contrasted with other possible means of affecting an "around-the-the-corner" NLOS sensor.
The primary concept works by creating a three-dimensional acoustic diffraction grating in open air. This is done by horizontally transmitting a plane-wave acoustic signal of known period. The resulting periodic regions of compression and rarefaction in the atmosphere will propagate at a speed proportional to a number of factors, most predominantly temperature and wind speed. If a radar signal of an appropriately chosen wavelength (proportional in length to the acoustic wavelength) is transmitted into the advancing parallel acoustic wave fronts, then a minute amount of energy will be reflected from each wavefront. By choosing the periods of the acoustic and radar transmissions correctly, the reflected electromagnetic contribution from each acoustic wavefront will add constructively and coherently (Bragg principal) to create a redirected electromagnetic beam propagating at an angle according to Snell's law.
Study results indicated that augmented NLOS sensing based on radio-acoustic detection principles is possible with detection probabilities exceeding 90%, but only for ranges of 30 to 50 m under ideal environmental conditions. The primary limitations on range performance derived from the lack of return signal energy as a result of two factors:
the small density gradient existing between regions of sound-compressed and sound-rarefied air or and,
the lack of focusing provided by acoustic plane waves as opposed to that observed in monostatic radio-acoustic sounding scenarios which employ spherical acoustic waves to successfully sense at long ranges (kilometers).
Results showed that various enhancement techniques can drastically improve the performance of the radio-acoustic and NLOS sensor, but at the expense of covertness and in some cases degraded mobility.
Charge-Coupled Devices for Analog-to-Digital Conversion
Robert Michelson's thesis [29] topic was the design of a novel analog-to-digital converter using charge-coupled devices.
Charge coupling, having been introduced in the late 60s, was a relatively new concept in metal-oxide semiconductor (MOS) technology at the time this thesis was written. Charge coupling provides the basic functions of data storage and transfer of both digital and analog data [30]. In addition, charge-coupled devices feature the principal advantages of presently existing MOS technology such as the basic fabrication steps, small surface area, and low power consumption.
Charge Coupled Devices (CCD) operate by transferring quantities of charge between potential wells created in a doped semiconductor material just below the semiconductor-insulator interface. These potential wells are actually inversion layers formed in the semiconductor material when a positive voltage is applied to an electrode above the insulator. Since the electrode is electrically insulated from the semiconductor material, an electrostatic field is produced which repels majority carriers (holes) and attracts minority carriers (electrons). Once an inversion layer has been established, charge can be injected into the potential well by any method that is capable of creating minority carriers. A sufficiently large positive voltage applied to the electrode will induce avalanche breakdown in the semiconductor material. During the avalanche breakdown, electrons are literally ripped from the outer shells of the substrate atoms nearest the semiconductor-insulator interface where the electrostatic fields are most intense. These liberated electrons then are held within the potential well created by the positive voltage on the electrode, and constitute an input to that well. Another input technique for entering charge is to create an N-region in the P-substrate which will act as a source of minority carriers. Applying a bias to the resulting P-N Junction while an inversion region is present nearby, will result in conduction of minority carriers from the N-region to the potential well. These quantities of charge that accumulate within the potential wells are referred to as "packets", and can be used to represent either analog or digital information. A third technique is to generate minority carriers within the semiconductor by exposing it to localized electromagnetic radiation (especially that falling within the visible range). Those minority carriers generated within a diffusion length of the potential well will accumulate in the well in proportion to the photon density.
When several elements are placed in a row on a common substrate, a charge packet in the first potential well can be made to propagate sequentially from well to well. In general, a two-phase clock can be used to achieve unidirectional movement; however, if a three-phase clock is used, bidirectional movement as possible. CCDs have found their greatest utility as video elements in cameras where impinging light is captured in an array of potential wells within a substrate and then clocked out of the array.
The results of this thesis showed that an 8-bit CCD-A/D could be designed that incorporates the desirable properties of several conversion techniques. A simulation program permitted the evaluation of the CCD-A/D design as a function of temperature, transfer efficiency, and clock rate. The simulation results showed that the effects of temperature and clock rates are closely related.
Transfer efficiency was found to be of less importance due to the relatively short delay lines employed in the converter. Data was obtained from the simulation program for a wide range of temperature-clock rate combinations. This data revealed regions of operation subject to given sets of constraints.
Analysis of the time constraints associated with the various components showed that the maximum theoretical conversion time was approximately 215 ns (slow by today's standards). The CCD-A/D converter was faster than many successive approximation schemes of the early 1970s, but somewhat slower than state-of-the-art parallel converters of the time.
Economically, a monolithic 8-bit CCD-A/D was shown to be comparable in chip area to standard TTL MSI, and it was therefore estimated that a CCD-A/D such as this would also be of comparable cost and production quantities.
As well as demonstrating utility, versatility, and potential economy, it was shown that the power requirements for a monolithic CCD-A/D converter would be approximately 2 mW, or a reduction of 500 times the power required for 1970s vintage converters. This, coupled with its small size and good speed/cost ratio, made the CCD-A/D converter a viable state-of-the-art alternative to then present A/D converters.
Prof. Michelson conducting an interview at the U.S. Army-sponsored "1st US-European Micro Air Vehicle Competition/Demonstration" in Garmisch Germany.
Design of Technology Demonstrations and Assessment of Micro Air Vehicle Technologies
Prof. Michelson has been a consultant to the U.S. Army and the Indian Ministry of Defence, responsible for defining the rules for and helping to organize the 1st U.S.-Asian Micro Air Vehicle Demonstration in Agra India (2008).[31][32] He performed similar duties for the U.S. Army in defining the 1st US-European Micro Air Vehicle Competition/Demonstration in Garmisch Germany (2005).[33] Michelson is often consulted regarding technology demonstrations, especially those having to do with aerial robotics, because of his unique experience in conducting successful events such as the International Aerial Robotics Competition for which he has been the creator and organizer for more than two decades. Michelson participated in the initial formulation of the DARPA Grand Challenge as a consultant, as well as advising the Canadian UVS community during their attempts to create a national collegiate competition to detect and combat improvised explosive devices (IED).
REFERENCES
- Michelson, R.C., "Tracking of the Florida Manatee,” ISA Transactions, Vol. 21, No. 1, 1982, pp. 79 - 85
- Michelson, R.C., “The Automated Remote Tracking of the Florida Manatee (Trichechus manatus ),” Proceedings of the 1981 IEEE SOUTHEASTCON, Huntsville, Alabama, April 1981, pp. 96 - 100
- Michelson, R.C., “Tracking of the Florida Manatee (Trichechus manatus ),” Proceedings of the 18th Annual Rocky Mountain Bioengineering Symposium, Laramie, Wyoming, April 1981
- Michelson, R.C., Breedlove, J., Jenkins, H.H., “Automated Tracking of the Florida Manatee (Trichechus manatus),” Final Report No. NAS10-9097-F, June 1978
- Sjoberg, E., Michelson, R.C., “Environment and Radar Operation Simulator,” Proceedings of the NAAG Panel XIV (EW) Group, Brussels, Belgium (invited paper), January 1978
- Sjoberg, E., Cole, S., Michelson, R.C., “Environment and Radar Operation Simulator,” Proceedings of the Sixteenth Annual U.S. Army Operation Research Symposium (AORS XVI), 12-14 October 1977, Fort Lee, Virginia
- Sjoberg, E.S., Cole, S.N., Flynt, E.R., Michelson, R.C., Vining, T.L., “Environment and Radar Operation Simulator,” ECOM-74-0272-F, Final Report, September 1977
- Butterworth, C., Michelson, R.C., Wallace, T., “Ka-Band Linear ECM Source (KABLES),” Final Report No. F33615-81-C-1530-F, June 1984
- Michelson, R.C., “Advanced Vehicle Control Systems,” Proceedings of the Workshop on Intelligent Vehicle Highway Systems and Advanced Transportation Technologies, Atlanta, Georgia, July 14 - 16, 1991
- "Battery State of Charge Detector with Rapid Charging Capability and Method", USPO number = 6,094,033, 7/25/2000
- Brazell, J., Michelson, R.C., “Automatic Control of a Truck-Mounted Drill Rig,” presented at the International Symposium on Mine Mechanization and Automation, Colorado School of Mines, Golden, CO, June 10 - 13, 1991
- Brazell, J., Michelson, R.C., “Automation of a Truck-Mounted Drill Rig,” Proceedings of the American Society of Civil Engineers, Cambridge, Massachusetts, April 13 - 16, 1991, pp. 272-277
- Michelson, R.C., Brooks, R., Scheer, J.A., Butterworth, C., et al, “Direct Support and General Support Maintenance Manual for the Georgia Tech Coherent Repeater,” April 1982
- Michelson, R.C., Brooks, R., Scheer, J.A., Butterworth, C., et al, "Operator’s Training and Maintenance Manual for the Georgia Tech Coherent Repeater,” April 1982
- http://pdv.cs.tu-berlin.de/MARVIN/index.html , "Multi-purpose Aerial Robot Vehicles with Intelligent Navigation", Technische Universität Berlin, 10-23-2007, accessdate=01-23-2009
- Michelson, R.C., Williamson, F.R., Brooks, R., “Indirect Fire Simulator- Cue System Development,” Final Report, Contract No. DAAG08-78-C-0191-F, January 1980
- Michelson, R.C., Brooks, R., Taylor, K.P., “Sonar Scan Converter,” Final Report No. N00612-79-D-8004-HR53-F, June 1984
- Irwin, D., Brooks, R., Michelson, R.C., et al, “Advanced Surveillance and Target Acquisition Radar (ASTAR) Prototype,” Final Report on Contract No. DAAK20-82-C-0144, February 1983
- Colozza, A., Michelson, R.C., et al., “Planetary Exploration Using Biomimetics - An Entomopter for Flight on Mars,” Phase II Final Report, NASA Institute for Advanced Concepts Project NAS5-98051, October 2002
- “Entomopter and Method for Using Same”, U.S. Patent No. 6,082,671, July 4, 2000
- “Reciprocating Chemical Muscle (RCM) and Method for Using Same”, U.S. Patent No. 6,446,909, September 10, 2002
- Englar, Robert J., Smith, Marilyn J., Kelley, Sean M., and Rover III, Richard C., “Development of Circulation Control Technology for Application to Advanced Subsonic Transport Aircraft, Part I: Airfoil Development” AIAA Paper No. 93-0644, Log No. C-8057, published in AIAA Journal of Aircraft, Vol. 31, No. 5, pp. 1160-1168, Sept-Oct 1994
- Englar, Robert J., Smith, Marilyn J., Kelley, Sean M., and Rover III, Richard C., “Development of Circulation Control Technology for Application to Advanced Subsonic Transport Aircraft, Part II: Transport Application” AIAA Paper No. 93-0644, Log No. C-8058, published in AIAA Journal of Aircraft, Vol. 31, No. 5, pp. 1169-1177, Sept-Oct 1994
- Colozza, A., Michelson, R.C., et al., “Planetary Exploration Using Biomimetics - An Entomopter for Flight on Mars,” Phase II Final Report, NASA Institute for Advanced Concepts Project NAS5-98051, October 2002
- Michelson, R.C., Alford, S.T., Echard, J.D., Gostin, L.L., Lunsford, G.H., Scheer, J.A., “Remote Detection of Natural Gas Leaks from Buried Utility Pipes by Electromagnetic Means,” Final Report, Contract No. GRI-50084-252-112 (subcontract to the Philadelphia Electric Company; prime to the Gas Research Institute), June 1986
- Michelson, R.C., Ahuja, K.K., Scheer, J.A., et al, "Feasibility of Applying Radio-Acoustic Techniques to Non Line-of-Sight Sensing,” 15th AIAA Aeroacoustics Conference, Long Beach, CA, October 25 - 27, 1993
- Michelson, R.C., Ahuja, K.K., Scheer, J.A., et al, “Non Line-of-Sight Sensor,” DARPA, A-9271 Final Report, Contract DAAA91-92-C-0098, March 1993
- May, P.T., Strauch, R.G., Moran, K.P., and Ecklund, W.L., "Temperature Sounding by RASS with Wind Profiler Radars: A Preliminary Study," IEEE Transactions on Geoscience and Reote Sensing, Vol. 28, No. 1, January 1990, pp 19-27
- Michelson, R.C., “Charge-Coupled Devices for Analog-to-Digital Conversion,” Georgia Institute of Technology, November 1974, pages = 76
- Barbie, D.F., "Charge-Coupled Devices, " The University of Michigan Engineering Summer Conference on Advanced Infrared Technology, July 16-20, 1973
- http://www.nal.res.in/MAV08/orgcomitte.htm, MAV08 Organizing Committee, accessdate=03-19-2009
- 1st US-Asian Demonstration and Assessment of Micro Aerial Vehicle (MAV) and Unmanned Ground Vehicle (UGV) Technology - Schedule of Events, Abstracts and Profiles, 1st US-Asian Demonstration and Assessment of Micro Aerial Vehicle (MAV) and Unmanned Ground Vehicle (UGV) Technology, National Aerospace Laboratories, ADRDE, US Army RDECOM, March 10-15, 2008, (also accessible on the internet at: http://www.nal.res.in/MAV08/MAV-pdf/mavabstracts.pdf), accessdate=03-22-2009, pages = 70
- http://aeromav.free.fr/MAV05/aeromav/vitae/, title=MAV05 organizers' vitae from remaining documents at MAV05 website, accessdate=03-19-2009}}